MFC-5840CN FAQs & Troubleshooting MFC-5840CN Not your product? Sort by: Updated Date Popularity 3 Results 1. 11/22/2011 When I print, the pages are smudged with ink. What should I do? 2. 11/06/2009 One or more of my colors are not printing (blank). What can I do? 3. 08/24/2006 Why are my sent faxes always received with a black vertical line down the page? Fax FAQs & Troubleshooting